CURRENT STATUS OF JMTR

Transcription

1 CURRENT STATUS OF JMTR M. Ishihara, N. Kimura, N. Takemoto, M. Ooka, M. Kaminaga, T. Kusunoki, Y. Komori and M. Suzuki Neutron Irradiation and Testing Reactor Center Japan Atomic Energy Agency, 4002 Narita, Oarai, Higashiibaraki, Ibaraki, , Japan ABSTRACT The Japan Materials Testing Reactor (JMTR) in Japan Atomic Energy Agency (JAEA) is a light water cooled tank type reactor with 50MW thermal power. From its first criticality in March 1968, the JMTR has been utilized for fuel/material irradiation examinations of LWRs, HTGR, fusion reactor as well as for RI productions under its transportation advantage that the JMTR and hot laboratory is connected by a canal. In August 2006, the JMTR operation was once stopped to make a check & review for the reoperation discussed by internal as well as external committees. Moreover, there were user s strong requests for the JMTR reoperation from various fields, such as nuclear power industries, universities, radioisotope production companies. As a result of the national discussion, the JMTR was determined, finally, to restart after necessary refurbishment works. The refurbishment works were started from the beginning of JFY 2007, and replaced were motors of primary and secondary cooling pumps, nuclear instrumentation system, process control system, safety protection system and so on. The refurbishment was finished in March 2011 taking four years as planned schedule. Unfortunately, at the end of the JFY 2010 on March 11, the Great-Eastern-Japan-Earthquake occurred, and functional tests before the JMTR restart, such as cooling system, reactor control system and so on, were delayed by the earthquake. Moreover, a detail inspection found some damages such as small cracks in the concrete structure, ground sinking around the reactor building. Consequently, the restart of the JMTR will delay from June 2011 to this year to assess the safety of the facility. The safety evaluation after the earthquake disaster has been carried out aiming at the restart of the JMTR. The renewed JMTR will be started from JFY 2012 and operated for a period of about 20 years until around JFY The usability improvement of the JMTR, e.g. higher reactor availability, shortening turnaround time to get irradiation results, attractive irradiation cost, business confidence, is also discussed with users as the preparations for re-operation. 1. Introduction The Japan Materials Testing Reactor (JMTR) in Japan Atomic Energy Agency (JAEA) is a light water cooled tank type reactor with thermal power of 50MW. The JMTR is connected with the hot laboratory by a water canal as shown in Fig.1. The purpose of the JMTR construction is to perform irradiation tests for LWR fuels, materials to establish domestic technology for developing nuclear power plants, to produce radio isotopes and to conduct education and training. The first criticality was achieved in March 1968, and the JMTR has been utilized for basic and applied researchers on

2 fuels/materials of fission reactors and fusion reactors. Power ramping tests for the nuclear fuels were, for example, performed to study the integrity/safety of fuels. Radioisotopes were also produced using the JMTR, and these were widely used in the medical treatment and industries [1-3]. Top view of the core is shown in Fig.2. The core of the JMTR consists of 22 or 24 (for high burn-up core) standard fuels, five control rods with fuel flowers, reflectors and H-shaped beryllium frame. Specifications of the JMTR are shown in table 1. As shown here, maximum twenty capsules with in-situ instrumentation, such as temperature, fluence and so on, are possible to install in the core. Post Irradiation Examinations (PIEs) carried out in of the JMTR hot laboratory are shown in Fig.3. Wide variety of PIEs is carried out in the hot laboratory, where four kinds of cells, concrete cells, lead cells, iron cells etc. The reactor operation was stopped from August, 2006, and then the refurbishment works started from the beginning of JFY 2007 by the user s strong request to the JMTR utilization. The renewed and upgraded JMTR will restart JFY 2012, and will operate for a period of about 20 years (until around JFY 2030). Fig.1. Outline of the JMTR. Fig.2. Top view of the Core.

3 Fig.3. PIEs carried out in the JMTR Hot Laboratory. Table.1 Specifications of the JMTR. Reactor Power 50MWt Fast Neutron Flux (Max.) n/m 2 s Thermal Neutron Flux (Max.) n/m 2 s Flow Primary Coolant 6,000 m 3 /h Coolant Temperature 49 / 56 Core Height 750mm Fuel Plate type, 19.8% 235 U Irradiation Capability (Max.) 60(20*) capsules Fluence/y (Max.) n/m 2 y dpa of Stainless Steel (Max.) 4 dpa Diameter of Capsule mm Temp. Control (Max.) 2,000 *: Capsule with in-situ measurement 2. JMTR Refurbishment Program Repairing and replacement works of the JMTR have been carried out according to the following process. (1) Investigation of Aged Components Aged components were surveyed and selected by evaluating whether those could be used safety after re-operation of the JMTR. (2) Replacement of Reactor Components Replacements were carried out within the range of licensing permission of the JMTR. Replacements of the systems and components, such as, boiler system, refrigerator for air conditioning system, power supply system, air supply/exhaust system, process control and instrumentation system, and so on, were conducted. (3) Installation of New Irradiation Facilities Corresponding to the user's requests, new irradiation facilities, such as test facilities for materials/fuels, production facility for medical isotopes etc. are being installed.

4 The JMTR refurbishment schedule is shown in Table 2. Fig. 4 JMTR Refurbishment Schedule. 3. Future Plan of JMTR After finishing the refurbishment works, the JMTR will be operated for a period of about 20 years until around JFY The expected utilization fields of irradiation are: 1) LWR materials and fuels safety research, which includes the safety management, aging management of LWRs. 2) Progress of science and technologies, which includes the development of fusion reactor materials, development of HTGR (High Temperature Gas cooled Reactor) fuels and materials, the basic research on nuclear energy, etc. 3) Expansion of industrial use, which includes the production of silicon semiconductor for the hybrid car and the production of 99m Tc for the medical diagnosis medicine. 4) Education and training of nuclear scientists and engineers. Availability factor of the JMTR would be increased with increasing the irradiation utilization. After reoperation in a steady state, availability factor of the JMTR will increase up to be at 60% to 70%, 210 days (7 cycles) /year to 240 days (8 cycles) / year. [4] Moreover, the JMTR will contribute to the research & development utilization as well as the industrial utilization by offering excellent irradiation technology. In irradiation, an attractive irradiation test will be proposed by developments of advanced technologies such as new irradiation technology, new measurement technology and new PIE technology. Furthermore, the cooperation with various nearby PIE facilities surrounding the JMTR will be established to extend the capability of PIEs after ongoing discussion with nearby facilities.

5 In Asian area, some excellent testing reactors are operated now. Each of them has individual features and plays complementary role in each other. The JMTR has a plan to contribute greatly to users by construction of the internationally utilized facility as an Asian center of testing reactors. 3.1 Birth of the Nuclear Techno-park with the JMTR In June 2010, Japanese Government selected 14 specialized projects for advanced research infrastructure in order to promote basic as well as applied researches. One of these 14 projects is the "Birth of the nuclear techno-park with the JMTR". In this project, new irradiation facilities and PIE equipments will be installed up to JFY The purpose is to build international research and development infrastructure. In the project, development of user-friendly environment especially for young and female researchers is highlighted. Schedule of new facility installation in the JMTR is shown in Fig.5; e.g. water-environment demonstration facility for LWRs, time control irradiation facility for 99mTc production by (n, γ) method, atomic level analyzer for PIE will be installed up to JFY FY Installation of advanced equipments Irradiation LWRs water-environment facilities demonstration test facility High accuracy time-control irradiation facility High accuracy capsule temperature control unit PIE High grade manipulator with visual equipments function Complex type fine texture analyzer For education& training Testing-reactor simulator for nuclear education Fig.5 Schedule of the project, Birth of the nuclear techno-park with the JMTR. 3.2 World Network and Asian Network Construction of world network is proposed by JAEA to achieve efficient facility utilization and providing high quality irradiation data by role sharing of irradiation tests among materials testing reactors. Framework of the MTRs composed of the World and Asian networks is shown in Fig.6. To construct the world network, the International Symposium on Material Testing Reactors (ISMTR) has been held every year. The objective of the symposium is to exchange the information among testing reactors to have mutual understanding of each reactor, and to construct the world network to make a complementary relationship. Furthermore, by construction of the world network and Asian network, it will be possible to achieve efficient facility utilization and possible to provide high quality irradiation data by role sharing of irradiation tests among materials testing reactors in the world. Moreover, the JMTR would contribute to promote fuels and materials study for LWRs, education & training etc. as a kernel of Asian MTR.

6 Fig.6 World network and Asian network for material testing reactors 3.3 Multipurpose Compact Test and Research Reactor The feasibility study on multipurpose compact test and research reactor is started for the growing demand for new research and test reactor in the world. This project will be proceeded with cooperation works by universities, industries and Asian countries as shown in Fig.7. This study would contribute to domestic and international human resource development. Furthermore, as a result, this study will contribute to the construction of nuclear power plant in these countries in future. Fig.7 Design and construction of Multipurpose compact test and Research Reactor. 4. Conclusions JAEA placed the JMTR as a materials testing reactor which supports the basic technology of the nuclear energy, and carried out the refurbishment of the reactor facilities taking four years from JFY 2007 for prolonged operation; the new JMTR would be re-operated promptly after the completion of seismic influence evaluation. New irradiation facilities are under installation in the JMTR; LWR fuels/materials irradiation facilities by the "Birth of the nuclear techno-park with the JMTR", industrial use for RI production, and so on. Furthermore,

7 new irradiation facilities are also under installation, which would be completed by JFY The new JMTR would be one of the kernel irradiation testing reactor in Asia, and contribute to the research and development utilization as well as the industrial utilization by offering advanced irradiation/post-irradiation technologies. Moreover, new JMTR contribute to the human resource development for domestic as well as foreign researcher/engineers including Asian countries, where nuclear power plants will be planned to construct. References [1] Department of JMTR, "The Course of JMTR," (2006) [2] Neutron Irradiation and Testing Reactor Center, "Proceeding of the international symposium on materials testing reactors," JAEA-Conf (2008) [3] Department of JMTR, "JMTR Japan Material Testing Reactor," booklet, (2005) [4] N. Takemoto et al., Investigation on High Availability-factor Achievement of JMTR How to Achieve 60% Availability-factor-, JAEA-Review (2008)